This invention relates to testing soil and, more particularly, to determining the dynamic parameters of soil.
In order for an architect or civil engineer to design a building or structure that is adequate to withstand dynamic ground forces, it is necessary for him to know the parameters of the soil that will ultimately support the building or structure, and in particular the dynamic parameters of such soil. This information is needed for two principle reasons. First, it is needed so that adequate building support and design will be provided. Second, it is needed so that the support pilings can be driven with a force adequate to drive them into the soil, but inadequate to damage surrounding structure or buildings. More specifically, by knowing the dynamic parameters of the soil, an architect or engineer can determine the amount of force that can be applied to a pile during a pile driving operation without such force having a detrimental effect on surrounding buildings or structure, such as breaking the windows of such buildings or structures, for example.
The most commonly used prior art technique for determining the dynamic parameters of soil requires the obtaining of soil samples (core samples). These samples are analyzed in detail in a suitable laboratory. The results are often not as accurate as desired The principle reason for the resultant inaccuracies relates to the change in the boundary conditions created when the soil is tested in this manner. That is, because the soil is removed to a laboratory, the natural boundary conditions existing at the soil site do not exist during analysis. To the extent that the boundary conditions effect the in situ dynamic parameters of the soil, the laboratory analysis is in error.
Therefore, it is an object of this invention to provide a method of determining the dynamic parameters of soil without requiring the removal or undue disturbance of the soil, i.e., without disturbing the natural boundary conditions of the soil.
It is a further object of this invention to provide a method of and an apparatus for determining the dynamic parameters of soil in situ.
It is also an object of this invention to provide an apparatus for rapidly and accurately determining the dynamic parameters of soil in situ.